1. Field of the Invention
The invention is in the technical field of fishing equipment. More particularly, the invention is in the technical field of delayed release bait containers that are intended for use in fish and shellfish fisheries.
2. Description of the Prior Art
Today, generally, crustaceans such as lobsters, crabs and shrimp, are caught with baited traps. In addition, large numbers of fish, such as sablefish and other bottom fish, are caught in baited traps or pots. Crustaceans and fish are attracted to, and lured within, the pots by the odor of bait, which usually comprises a food substance preferred by the particular targeted animal. Typically, fish or shellfish byproducts are used as bait; however manufactured baits are sometimes used. Bait can be hung within the pot, or it can be held in bait containers that allow the odor of the bait to escape. Two problems with such systems exist. First, as soon as bait is exposed to water, the attractive odor substances contained within the bait begin to quickly leach out. Because the quantity of bait is limited in a pot, the effectiveness of baited pots lasts for a relatively short period after the pot is deployed in the sea. Second, bait left hanging free, or bait in containers with large holes in them, allow sea creatures, such as sea lice to enter the container and eat the bait quickly. As a result, much of the effort and expense of pot fishing involves the frequent renewal of bait. Generally, re-baiting is necessary long before an adequate catch has accumulated. It has been recognized, therefore, that if fresh bait replacement can be delayed, avoiding the expenditure of labor and boat operating time, the actual catch per unit effort, and hence the profitability, of the fishing operation can be significantly increased.
To that end, several devices for holding bait have been developed. Examples of such devices are found in following U.S. Patents: U.S. Pat. No. 4,914,856 discloses a trap made of plastic that has a door for loading and a number of slits formed in it. The device can be loaded and suspended in a pot and released into the sea. While an improvement over hanging the bait openly, the slits allow water and some organisms to enter immediately, thus shortening the effective life of the bait. U.S. Pat. No. 5,617,669 is another example of a simple container for holding bait that does little to protect the bait from rapid exhaustion.
Others have developed systems for time-release of the bait. In this way, the bait is kept in a container and not opened for a set time. After a desired interval, the container is opened and the bait is allowed to mix with the seawater. Such devices allow for a prolonging of the bait for an extended time. Examples of these devices include: U.S. Pat. No. 4,143,479, which teaches a sealed bag that is held in a frame. A knife blade is secured to a track and is held by a restraint. The restraint is designed to dissolve in seawater after a given time. Once the restraint fails, the knife blade is pulled along the track and the bag is opened. While novel, this system has a number of drawbacks. First, the knife blade has a high potential of failure. Second, the device is difficult and perhaps dangerous to operate and configure with gloves and in typical fishing environments. Lastly, if the bag is successfully opened, target species and other organisms can quickly consume the bait, as there is no mechanism that prevents access to the bait. U.S. Pat. No. 6,453,602 teaches a canister that has a door for loading and exposing the bait. The door is biased open by an elastic cord that is restrained by a corrodible link. Because the container is not water tight, bait is immediately exposed to seawater, which leads to immediate degradation of the bait prior to release of the corrodible link. Once the link corrodes, the lid is released and the bait is further exposed to the seawater. Once the door is open, however, this device is no better than simply hanging the bait fully exposed. As such, the bait does not last long once the container is opened. U.S. Pat. No. 3,842,529 teaches a number of methods of using corrodible materials to hold bait and release it after a desired time has elapsed. In one most embodiment, he teaches containers that have corrodible lids or a bag with a corrodible clip that, once corroded expose the bait. The problem with these designs is, one again, once the container is opened, the bait is fully exposed to seawater and organisms and sea water is allowed to leak into the container prior to the container being opened leading to significant premature bait degradation Finally, a UK patent, GB 2,359,473 teaches another container that is sealed after loading. A time-release mechanism is installed to cause the seal to open, exposing the bait. This too suffers from the problem of having large holes that permit seawater and organisms to enter the container and rapidly deteriorate the bait after the time-release function has worked.